Nationwide
This U.S. Drought Monitor (USDM) week saw degradations across the areas of the West, Southeast, and Mid-Atlantic, while rainfall during the past week led to improvements in drought-affected areas of the South, Plains, and Midwest.
In the Midwest, widespread improvements occurred after another round of precipitation last week, removing drought areas on the map in Iowa, Missouri, Illinois, Indiana, and Ohio. In these areas, precipitation totals ranged from 2 to 5 inches. Similarly, significant rainfall was observed in parts of Texas, Oklahoma, and Louisiana, prompting targeted improvements.
Out West, generally dry conditions prevailed across much of the region, although modest precipitation totals were observed in areas of the Pacific Northwest, Northern California, Intermountain West, and Southwest, with the highest totals logged in California. Despite the much-needed precipitation, conditions deteriorated across Oregon, California, Nevada, Wyoming, Montana, and New Mexico. In the Hawaiian Islands, conditions have improved significantly during the past two months due to historic rainfall events observed across the island chain. Elsewhere, dry conditions continued across much of the Southeast and Mid-Atlantic, leading to degradation in conditions from Virginia to Florida.
Coming into April, mountain snowpack conditions remain well below normal despite this week’s precipitation across the higher elevations of the Cascades, Sierra, and Rockies. According to the Natural Resources Conservation Service (NRCS) SNOw TELemetry (SNOTEL) network (April 7), region-level (2-digit HUC) snow water equivalent (SWE) values (percent of median) are as follows: Pacific Northwest 50%, Missouri 58%, Upper Colorado 26%, Great Basin 18%, Lower Colorado 17%, Rio Grande 13%, and Arkansas-White-Red 10%. In California, statewide snowpack is 16% of normal (April 7), with the Southern Sierra at 27%, the Central Sierra at 19%, and the Northern Sierra at 5%.
The West
Conditions continued to deteriorate in the region with degradations made across southern Oregon, Northern California, southwestern Montana, northwestern Wyoming, and New Mexico. Despite some precipitation falling across the region’s mountain ranges this week, snowpack conditions remain extremely poor, with the remaining snowpack primarily confined to the highest elevations.
In Colorado, NRCS is reporting statewide SWE at the lowest on record. Historically, median peak SWE in Colorado occurs on April 8; however, this year, peak SWE occurred on March 8. In Washington state, the Department of Ecology issued a statewide emergency drought declaration as projected water supplies are expected to be well below normal levels. In the Colorado River Basin, Lake Powell is 24% full, while Lake Mead is 33% full, according to the U.S. Bureau of Reclamation.
Across areas of the Far West, very dry conditions were observed during the past 30-day period (March 7 to April 7), with record to near-record dryness at the following locations: Eugene, OR (10th driest; -2.57 inches); Medford, OR (9th driest; -1.38 inches); Crescent City, CA (2nd driest; -5.58 inches); Mount Shasta, CA (driest on record; -5.35 inches); San Francisco, CA (5th driest; -2.34 inches); Santa Cruz (driest on record; -3.13 inches); Monterey, CA (3rd driest; -2.8 inches), and San Diego, CA (driest on record; -1.24 inches).
The High Plains
On this week’s map, rainfall (1 to 4 inches) during the past week led to targeted improvements in far eastern portions of Kansas and Nebraska. Meanwhile, conditions deteriorated on the map in areas of central and western Kansas, and southwestern South Dakota.
For the week, average temperatures were 4 to 10+ F below normal across much of the region, with the greatest departures observed in the Dakotas. Looking at climatological rankings for the past 30-day period (March 7 to April 7), several locations ranked among their driest on record, including Dodge City, KS (driest on record; -1.51 inches); Goodland, KS (driest on record; -1.05); and Manhattan, KS (2nd driest; -1.81 inches). In terms of hydrologic conditions, the U.S. Geological Survey is reporting below to much below normal streamflows across southwestern South Dakota, southern Nebraska, and central/western Kansas.
The South
On this week’s map, improvements were made in drought-affected areas of Texas, Oklahoma, Louisiana, and Arkansas, while areas of Tennessee saw degradations.
In terms of precipitation during the past week, moderate to heavy rainfall accumulations (ranging from 3-6 inches) were observed in Texas, Oklahoma, and isolated areas of Louisiana. In Arkansas, some beneficial rainfall fell in the far-western portion of the state, leading to a boost in streamflow. However, dry soils and significant precipitation deficits remain across the state, with the NDMC CMOR tool showing many new impact reports during the past week. Looking at climatological rankings for the past 60-day period (February 7 to April 7), record to near-record dryness was observed in the region, including in Del Rio, TX (driest on record; -1.98 inches), Monticello, AR (4th driest; -5.7 inches), and Monroe, LA (7th driest; -6.69 inches). In Texas, Water for Texas (April 7) reports statewide reservoirs at 74% full, with eastern reservoirs in good condition, while many western and southern reservoirs remain below normal. Average temperatures for the week were above normal across the region (2 to 12+ F). — UNL Drought Monitor
